- Also known as fortification spectrum, fortification figure, fortification of Vauban, geometrical spectrum, herringbone, Norman arch, scintillating scotoma, and flittering scotoma. The term teichopsia comes from the Greek words teichos (wall), and opsis (seeing). Its introduction is attributed to the British physician Hubert Airy (1838-1903). Today it is used to denote a * geometric visual hallucination consisting of an extremely bright, sometimes coloured, zigzag line or 'fortification wall', which may begin near the fovea in one hemifield, and then spread out towards the periphery of the hemifield without touching the vertical meridian. For a further description of this phenomenon, see the entry Fortification spectrum.ReferencesAiry, H. (1870). On a distinct form of transient hemiopsia. Philosophical Transactions ofthe Royal Society ofLondon, 160, 247-264.Levene, J.R. (1975). Sir G.B. Airy, F.R.S. (18011892) and the symptomatology of migraine. Notes and Records ofthe Royal Society of London, 30, 15-23.Wilkinson, F. (2004). Auras and other hallucinations: Windows on the visual brain. Progress in Brain Research, 144, 305-320.
Dictionary of Hallucinations. J.D. Blom. 2010.